Police searched Leonardtown High school and two courthouses Thursday morning in St. Mary’s after receiving a call of a bomb threat. No devices were found.

Bomb-detecting K-9 units from St. Mary’s, Calvert and Charles counties searched the circuit court, district court and the high school. As of 9:30 a.m., the circuit courthouse had been given the all-clear, according to the St. Mary’s sheriff’s office.

The high school was given the all-clear at 10:34 a.m. after being on lockdown for about two hours, Mike Wyant, director of safety and security for St. Mary’s schools, said from the emergency command center in Leonardtown. Students and staff remained in classrooms during the search, he said.

The county’s emergency communications center received one call at 8:10 a.m. of a bomb at Leonardtown High School as well as the circuit and district court buildings in Leonardtown, according to the sheriff’s office.

The school system posted an emergency update on the school’s website at about 8:30 a.m. saying law enforcement had informed the school of “a potential bomb threat at Leonardtown High School and several other locations in Leonardtown.”

The circuit court downtown was evacuated Thursday morning until a search confirmed no presence of a bomb, according to the sheriff’s office.

District court, per instructions from a judge there, was not evacuated, according to the sheriff’s office.